Enable clippy lint must_use_candidate as "warn"

Author: SpriteOvO

Cargo.toml

@@ -15,4 +15,5 @@ keywords = ["spdlog", "log", "logging"]
 categories = ["development-tools::debugging"]
 
 [workspace.lints.clippy]
+must_use_candidate = "warn"
 unused_trait_names = "warn"

spdlog-internal/src/pattern_parser/mod.rs

@@ -104,14 +104,17 @@ impl BuiltInFormatter {
         BuiltInFormatterInner::iter().map(BuiltInFormatter)
     }
 
+    #[must_use]
     pub fn struct_name(&self) -> &'static str {
         BuiltInFormatterInnerDiscriminants::from(self.0).into()
     }
 
+    #[must_use]
     pub fn placeholder(&self) -> &'static str {
         self.0.into()
     }
 
+    #[must_use]
     pub fn inner(&self) -> BuiltInFormatterInner {
         self.0
     }

spdlog-internal/src/pattern_parser/registry.rs

@@ -14,6 +14,7 @@ pub struct PatternRegistry<F> {
 }
 
 impl<F> PatternRegistry<F> {
+    #[must_use]
     pub fn with_builtin() -> Self {
         let mut registry = Self {
             formatters: HashMap::new(),

spdlog/src/kv.rs

@@ -100,13 +100,15 @@ pub struct Key<'a>(RefStr<'a>);
 
 impl Key<'_> {
     /// Gets the key string.
+    #[must_use]
     pub fn as_str(&self) -> &str {
         self.0.get()
     }
 }
 
 impl<'a> Key<'a> {
     #[doc(hidden)]
+    #[must_use]
     pub fn __from_static_str(key: &'static str) -> Self {
         Key(RefStr::new_static(key))
     }
@@ -187,6 +189,7 @@ pub struct KeyValues<'a>(KeyValuesInner<'a>);
 
 impl<'a> KeyValues<'a> {
     /// Gets the number of key-value pairs.
+    #[must_use]
     pub fn len(&self) -> usize {
         match self.0 {
             KeyValuesInner::Borrowed(p) => p.len(),
@@ -195,6 +198,7 @@ impl<'a> KeyValues<'a> {
     }
 
     /// Checks if there are no key-value pairs.
+    #[must_use]
     pub fn is_empty(&self) -> bool {
         match self.0 {
             KeyValuesInner::Borrowed(p) => p.is_empty(),
@@ -203,6 +207,7 @@ impl<'a> KeyValues<'a> {
     }
 
     /// Gets the value of the specified key.
+    #[must_use]
     pub fn get(&self, key: Key) -> Option<Value<'a>> {
         match self.0 {
             KeyValuesInner::Borrowed(p) => {
@@ -274,6 +279,7 @@ impl<'a> IntoIterator for KeyValues<'a> {
 }
 
 /// Represents an iterator over key-value pairs.
+#[must_use]
 pub struct KeyValuesIter<'a>(KeyValuesIterInner<'a>);
 
 impl<'a> Iterator for KeyValuesIter<'a> {

spdlog/src/level.rs

@@ -379,6 +379,7 @@ impl AtomicLevelFilter {
     const ORDERING: Ordering = Ordering::Relaxed;
 
     /// Creates a new `AtomicLevelFilter`.
+    #[must_use]
     pub fn new(init: LevelFilter) -> Self {
         Self {
             inner: atomic::Atomic::new(init.into()),